Brookfield, IL Political Map | Democrat & Republican Areas in Brookfield

Brookfield leans Democratic by roughly 24 points: about 62% of voters vote Democratic and 38% Republican.

 
Brookfield, IL block-group political-lean map
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About 78% of adults in Brookfield typically vote, above the U.S. average of about 62%. Among adults in Brookfield, ~48% vote Democratic, ~30% Republican, and ~22% don't vote. The map below shows estimated turnout by block group.

Brookfield, IL block-group voter-turnout map
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How Brookfield compares

Among cities within 25 miles, Brookfield leans more Democratic than 106 of 169 neighbors.

Brookfield runs about 12 points more Democratic than Illinois as a whole.

Politics vary noticeably by neighborhood within Brookfield. The northwest side is the most Democratic-leaning (D+35) and the south side is the least Democratic-leaning (D+15), a spread of about 20 points.

Why Brookfield leans the way it does

This analysis examined 14,881 data points per city to find what predicts political lean and turnout. The items below are a few correlations that stood out for Brookfield, not a ranked or complete list of what matters most.

Dense areas vote Democratic. About 96% of residents in Brookfield live in densely developed areas, about 59 points above the U.S. average of 36%. High college attainment predicts Democratic voting, and Brookfield sits in the top quarter (about 43%, above 89% of cities).

Walkability and Democratic lean

Places with a highly walkable street grid tend to lean Democratic; Brookfield, IL sits in the top tenth nationally on this measure. A walkable street grid does not change how people vote; it mostly reflects how urban a place is.

Why turnout in Brookfield looks the way it does

Areas with strong routine healthcare access turn out at higher rates. Brookfield is in the top quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. The dental-visit rate here is about 68%, about 8 points above the U.S. average of 60%. Learn more about the findings and methodology on the political spectrum map.

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Sources and methodology

Precinct-level voting records used to fit the model come from Illinois State Board of Elections, distributed by the Voting and Election Science Team. Demographic inputs come from the U.S. Census Bureau (ACS 5-year estimates and the 2020 Decennial Census). Health and environmental inputs come from the CDC (PLACES and the Environmental Justice Index). Land cover comes from the USGS and EPA. Election-day and lead-up weather come from PRISM 4km daily grids and the NOAA Global Historical Climatology Network. Mail-voting and election-administration patterns come from the MIT Election Lab's Survey of the Performance of American Elections. Block-group crime detail comes from CrimeGrade. Internet data and modeling support provided by ISPreports.org.

Modeling and analysis by the BestNeighborhood data science team. Full methodology and findings: political spectrum map.

Methodology reviewed by the BestNeighborhood data team. Last updated May 2026.